| 1. |
- Meingast, Arno, et al.
(författare)
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High resolution STEM investigation of interface layers in cemented carbides
- 2018
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Ingår i: International Journal of Refractory Metals and Hard Materials. - : Elsevier BV. - 0263-4368 .- 2213-3917. ; 72, s. 135-140
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Tidskriftsartikel (refereegranskat)abstract
- Cemented carbides with sub-micron grain size have increased the need to restrict grain growth during sintering. Commonly used inhibitors like V, Ti, and Cr have been observed to form interface layers in the interfaces between WC grains and the Co binder. Atomistic modeling has predicted the composition and thickness of the interface layers. Earlier, the interface layers have been characterized qualitatively using high resolution transmission electron microscopy (TEM). To get more information about the structure and composition of the interface layers in a Ti containing cemented carbide in this work, Z contrast imaging and spectroscopy using scanning transmission electron microscopy (STEM) have been combined. Elemental maps revealing the structure of the interface layers will be presented.
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| 2. |
- Sytnyk, Mykhailo, et al.
(författare)
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Tuning the Magnetic Properties of Metal Oxide Nanocrystal Heterostructures by Cation Exchange
- 2013
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 13:2, s. 586-593
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Tidskriftsartikel (refereegranskat)abstract
- For three types of colloidal magnetic nanocrystals, we demonstrate that postsynthetic cation exchange enables tuning of the nanocrystal's magnetic properties and achieving characteristics not obtainable by conventional synthetic routes. While the cation exchange procedure, performed in solution phase approach, was restricted so far to chalcogenide based semiconductor nanocrystals, here ferrite-based nanocrystals were subjected to a Fe2+ to Co2+ cation exchange procedure. This allows tracing of the compositional modifications by systematic and detailed magnetic characterization. In homogeneous magnetite nanocrystals and in gold/magnetite core shell nanocrystals the cation exchange increases the coercivity field, the remanence magnetization, as well as the superparamagnetic blocking temperature. For core/shell nanoheterostructures a selective doping of either the shell or predominantly of the core with Co2+ is demonstrated. By applying the cation exchange to FeO/CoFe2O4 core/shell nanocrystals the Neel temperature of the core material is increased and exchange-bias effects are enhanced so that vertical shifts of the hysteresis loops are obtained which are superior to those in any other system.
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